Nippon Professional Baseball (日本野球機構, Nippon Yakyū Kikō) or NPB is the highest level of baseball in Japan. Locally, it is often called Puro Yakyū (プロ野球), meaning Professional Baseball. Outside Japan, it is often just referred to as "Japanese baseball". The roots of the league can be traced back to the formation of the "Greater Japan Tokyo Baseball Club" (大日本東京野球倶楽部, Dai-Nippon Tōkyō Yakyū Kurabu) in Tokyo, founded in 1934, and the original circuit for the sport in the Empire two years later – Japanese Baseball League (1936–1949), and continued to play even through the final years of World War II.